<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>菜鸟教程(runoob.com)</title>
  <style>
  #myImg {
    border-radius: 5px;
    cursor: pointer;
    transition: 0.3s;
  }

  #myImg:hover {opacity: 0.7;}

  /* The Modal (background) */
  .modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.9); /* Black w/ opacity */
  }

  /* Modal Content (image) */
  .modal-content {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
  }

  /* Caption of Modal Image */
  #caption {
    margin: auto;
    display: block;
    width: 80%;
    max-width: 700px;
    text-align: center;
    color: #ccc;
    padding: 10px 0;
    height: 150px;
  }

  /* Add Animation */
  .modal-content, #caption {
    -webkit-animation-name: zoom;
    -webkit-animation-duration: 0.6s;
    animation-name: zoom;
    animation-duration: 0.6s;
  }

  @-webkit-keyframes zoom {
    from {-webkit-transform: scale(0)}
    to {-webkit-transform: scale(1)}
  }

  @keyframes zoom {
    from {transform: scale(0.1)}
    to {transform: scale(1)}
  }

  /* The Close Button */
  .close {
    position: absolute;
    top: 15px;
    right: 35px;
    color: #f1f1f1;
    font-size: 40px;
    font-weight: bold;
    transition: 0.3s;
  }

  .close:hover,
  .close:focus {
    color: #bbb;
    text-decoration: none;
    cursor: pointer;
  }

  /* 100% Image Width on Smaller Screens */
  @media only screen and (max-width: 700px){
    .modal-content {
      width: 100%;
    }
  }
  </style>
</head>
<body>

  <h2>图片模态框</h2>
  <p>本实例演示了如何结合 CSS 和 JavaScript 来一起渲染图片。</p><p>
    首先，我们使用 CSS 来创建 modal 窗口 (对话框), 默认是隐藏的。<p>
      <p>然后，我们使用 JavaScript 来显示模态窗口，当我们点击图片时，图片会在弹出的窗口中显示：</p>
      <img id="myImg" src="http://www.runoob.com/wp-content/uploads/2016/04/img_lights.jpg" alt="Northern Lights, Norway" width="300" height="200">

      <!-- The Modal -->
      <div id="myModal" class="modal">
        <span class="close">×</span>
        <img class="modal-content" id="img01">
        <div id="caption"></div>
      </div>

      <script>
      // 获取模态窗口
      var modal = document.getElementById('myModal');

      // 获取图片模态框，alt 属性作为图片弹出中文本描述
      var img = document.getElementById('myImg');
      var modalImg = document.getElementById("img01");
      var captionText = document.getElementById("caption");
      img.onclick = function(){
        modal.style.display = "block";
        modalImg.src = this.src;
        modalImg.alt = this.alt;
        captionText.innerHTML = this.alt;
      }

      // 获取 <span> 元素，设置关闭模态框按钮
      var span = document.getElementsByClassName("close")[0];

      // 点击 <span> 元素上的 (x), 关闭模态框
      span.onclick = function() {
        modal.style.display = "none";
      }
      </script>

    </body>
    </html>
